Resurgence and downshifts in alternative reinforcement rate

Resurgence refers to an increase in a previously suppressed target behavior with a relative worsening of conditions for a more recently reinforced alternative behavior. This experiment examined the relation between resurgence and the magnitude of a reduction in the rate of reinforcement for the alternative behavior. Groups of both male and female rats initially pressed a target lever for food on a variable-interval (VI) 30-s schedule. In a second phase, responding to the target lever was extinguished for all groups and pressing an alternative lever was reinforced on a VI 10-s schedule. Next, the rate of reinforcement for alternative behavior was reduced differentially across groups by arranging extinction, VI 80-s, VI 40-s, VI 20-s, or continued VI 10-s reinforcement. Target responding increased as an exponential function of the magnitude of the reduction in alternative reinforcement rates. With the exception that males appeared to show higher rates of target responding in baseline and higher rates of alternative responding in other phases, the overall pattern of responding across phases was not meaningfully different between sexes. The pattern of both target and alternative response rates across sessions and phases was well described quantitatively by the Resurgence as Choice in Context model.     

习得的语言范畴对注意前颜色范畴知觉的影响:一项ERP研究

该研究探讨了语言范畴对注意前颜色知觉的影响依赖于语言范畴与颜色长期联结还是其即时分类颜色,同时检验了习得的语言范畴是否能因果性地改变早期颜色知觉机能。采用G1、G2、B1、B2（前两者为绿色,后两者为蓝色）4种连续变化的颜色为材料。学习组和分类组被试分别接受6次和1次色词与颜色重组训练,学习4种颜色不同的新名称,并在之后均接受视觉Oddball脑电测试。训练结果显示：学习组稳定地习得了4种颜色的新名称,分类组能以新名称将颜色分为4类。测试结果显示：学习组的颜色知觉中出现了与习得语言范畴对应的偏侧化注意前颜色范畴知觉,分类组的颜色知觉中未出现与颜色分类对应的偏侧化注意前颜色范畴知觉。研究结果表明：语言范畴对注意前颜色知觉的影响依赖于语言范畴与颜色长期联结而非其即时分类颜色;习得的语言范畴能引起偏侧化注意前颜色范畴知觉,提示习得的语言范畴能因果性地改变早期颜色知觉机能。     

Cerebellar contributions to tactile perception in people with varying sensorimotor experiences: Examining the sensory acquisition hypothesis

The sensory acquisition hypothesis states that the sensory demand of a task is the most crucial factor in determining the level of cerebellar activity. The present study was conducted to examine whether the prediction of sensory demand holds when participants have different sensorimotor training experiences. Archery athletes and non-athletic control participants were asked to perform tactile discrimination tasks during fMRI scanning. In archery athletes, a pattern of reduced cerebellar activation accompanying higher sensory cortical activity was observed, whereas in non-athletic control participants the visual network was found to be in concert with extensive cerebellar activation. These findings are in accordance with the prediction that the cerebellum plays a supportive role for the cerebral cortex in sensory data acquisition.     

Territorial sense of community,ethnic prejudice and political orientation

This research focused on territorial sense of community and ethnic prejudice. In particular, we related these two constructs and investigated their relationship to individual characteristics (personal political orientation, contact with immigrants, etc.) and community‐level ones (such as ethnic composition and the political orientation of the local government). Two studies were conducted in four small towns in central and southern Italy. For each study, 160 people were contacted. The instruments used were a questionnaire, the Italian Sense of Community Scale and the Blatant Prejudice Scale. The results showed that territorial sense of community is not related to ethnic prejudice or to the ethnic heterogeneity of the territory. It was also found that people with right‐wing political sympathies revealed higher levels of prejudice than people with left‐wing sympathies. Finally, in a town with a stable and consolidated left‐wing orientation of the local government we found, when the influence of personal political orientation was controlled for, lower levels of prejudice than in a town with a right‐wing orientation. Copyright © 2008 John Wiley & Sons, Ltd.     

Peer Victimization in School: Exploring the Ethnic Context

ABSTRACT— This article provides an overview of recent research on peer victimization in school that highlights the role of the ethnic context—specifically, classrooms' and schools' ethnic composition. Two important findings emerge from this research. First, greater ethnic diversity in classrooms and schools reduces students' feelings of victimization and vulnerability, because there is more balance of power among different ethnic groups. Second, in nondiverse classrooms where one ethnic group enjoys a numerical majority, victimized students who are members of the ethnic group that is in the majority may be particularly vulnerable to self-blaming attributions. The usefulness of attribution theory as a conceptual framework and ethnicity as a context variable in studies of peer victimization are discussed.     

Effects of discriminatory interview questions and gender on applicant reactions

Justice and signalling theory were used to explain the effects of discriminatory interview questions on applicant reactions. Participants were randomly assigned to a hypothetical interview condition with four, two or no discriminatory questions. Discriminatory questions had a significant negative effect on participant’s reactions to the interview and interviewer; perceptions of employee treatment; and intentions to pursue employment, accept a job offer, and recommend the organization to others. Participants also responded less favorably to a female interviewer, and female interviewees reported more negative perceptions. In addition, a sequential model was supported in which discriminatory questions had a negative effect on reactions toward the interview and interviewer; reactions were positively related to organizational attractiveness; and organizational attractiveness was positively related to intentions to pursue employment, accept a job offer, and recommend the organization.     

On the law of Regular Minimality: Reply to Ennis

Ennis's critique touches on issues important for psychophysics, but the points he makes against the hypothesis that Regular Minimality is a basic property of sensory discrimination are not tenable.(1) Stimulus variability means that one and the same apparent stimulus value (as measured by experimenter) is a probabilistic mixture of true stimulus values. The notion of a true stimulus value is a logical necessity: variability and distribution presuppose the values that vary and are distributed (even if these values are represented by processes or sets rather than real numbers). Regular Minimality is formulated for true stimulus values. That a mixture of probabilities satisfying Regular Minimality does not satisfy this principle (unless it also satisfies Constant Self-Similarity) is an immediate consequence of my 2003 analysis. Stimulus variability can be controlled or estimated: the cases when observed violations of Regular Minimality can be accounted for by stimulus variability corroborate rather than falsify this principle. In this respect stimulus variability is no different from fatigue, perceptual learning, and other factors creating mixtures of discrimination probabilities in an experiment.(2) Could it be that well-behaved Thurstonian-type models are true models of discrimination but their parameters are so adjusted that the violations of Regular Minimality they lead to (due to my 2003 theorems) are too small to be detected experimentally? This is possible, but this amounts to admitting that Regular Minimality is a law after all, albeit only approximate: nothing in the logic of the Thurstonian-type representations per se prevents them from violating Regular Minimality grossly rather than slightly. Moreover, even very small violations predicted by a given class of Thurstonian-type models can be tested in specially designed experiments (perhaps under additional, independently testable assumptions). The results of one such experiment, in which observers were asked to alternately adjust to each other the values of stimuli in two observation areas, indicate that violations of Regular Minimality, if any, are far below limits of plausible interpretability.     

Ethnicity as a social context for the development of African-American adolescents

Does anticipated future racial discrimination undermine African-American adolescents' academic motivation and performance? Do face-to-face experiences with racial discrimination at school undermine African-American adolescents' academic functioning? Does African-American ethnic identity buffer these relations? This paper addresses these questions using two waves of data from a longitudinal study of an economically diverse sample of African-American adolescents living near Washington D.C. The data were collected at the beginning of the 7th grade and after the completion of the 8th grade. As expected, the experiences of day-to-day racial discrimination at school from one's teachers and peers predicted declines in grades, academic ability self-concepts, and academic task values. A strong, positive connection to one's ethnic group (our measure of ethnic identity) reduced the magnitude of the association of racial discrimination experiences with declines in both academic self-concepts and school achievement. Most youth responded to anticipated future discrimination with increased academic motivation.     

The chronometry of mental ability: An event-related potential analysis of an auditory oddball discrimination task

The relation between intelligence and speed of auditory discrimination was investigated during an auditory oddball task with backward masking. In target discrimination conditions that varied in the interval between the target and the masking stimuli and in the tonal frequency of the target and masking stimuli, higher ability participants (HA) displayed more accurate discriminations, faster response time, larger P300 amplitude, and shorter P300 and mismatch negativity (MMN) latency than lower ability participants (LA). Task difficulty effects demonstrated with variation in mask type indicate that the mask does not interfere with the detection of the deviant target stimulus, but rather that the target and mask are integrated as a single compound stimulus. The temporal effects suggest that the speed of accessing short-term memory is faster for HA than LA and, on the basis of the MMN latency, the effect is accomplished automatically, without focused attention. Moreover, the pattern of results obtained with these data support the view that the accuracy effects are determined by processing speed rather than discrimination ability. Comparator models that accommodate these effects are discussed.     

Titrating-delay matching-to-sample in the pigeon

The titrating-delay matching-to-sample (TDMTS) procedure offers researchers an additional behavioral task thought to capture some important features of remembering. In this procedure, the delay between sample offset and comparison onset adjusts as a function of the subject's performance. Specifically, correct matches increase the delay and incorrect matches decrease the delay, and steady-state titrated delays serve as the primary dependent measure. The present series of experiments investigated the effects of several procedural variables on performance in TDMTS procedures in an effort to elucidate better its features to allow for more precision in future use. Experiment 1 reports results from a parametric analysis of fixed-ratio response requirements on the sample key that indicated improved remembering in the form of higher daily titrated delay values as the requirement was increased. Experiment 2 investigated the extent to which the initial delay value in each session affected session-wide delay values. Results indicated that regardless of value of the initial delay, the subjects' performances adjusted the delay values in the direction of the known baseline delay-value levels. Experiment 3 manipulated the step size by which delay values were adjusted and the results indicated that larger step sizes increased both session-to-session variability and within-session range of titrated delay values, although the average values remained approximately the same. These results suggest that the TDMTS task serves as a promising procedure to study what many refer to as memory.